This invention relates to a floating crane comprising a main jib which can be deposited on deck and luffed by a luffing rope about a hinge working in bearings that can be moved along a horizontal track on the deck of the floating pontoon.
In conventional floating cranes the main jib is deposited on deck for a sea voyage by lowering it aft. This operation takes several hours to perform and calls for the assistance of a corresponding number of men. Being difficult and hazardous it is a fair weather operation. The main jib must first be placed in a given angular position. The jib support must then be unlocked and lowered. Finally, strong rope connections must be established from the mast to hook blocks and deck. This work must be done at a point some 10 meters ahead of the pontoon and about 20 meters above the water from a basket hanging from auxiliary hoisting tackle. The main jib must then be pulled up over dead center by taking in the luffing rope and paying out the hoisting rope and thus depositing the jib on a chair by lowering it aft.